Seeing the light railway

Security on public transport, particularly in London, has been under scrutiny in the media recently, and for very obvious reasons.

In order to enhance passenger and staff safety and deter vandalism, the docklands Light Railway commissioned the installation of a network of digital video recorders on all of its trains. The systems contract was awarded to Falcon Protec who, following extensive research and trials, selected Wavelet Technology for the supply of the core digital video recording hardware and software.

Wavelet says the cost implications resulting from vandalism, terrorism and assaults on staff and passengers can have substantial financial implications for any transport operator.

"Safety of staff and passengers and the security of physical assets can be greatly enhanced through the implementation of effective on-vehicle surveillance and security systems," says the company's Chris Williams.

"On-train surveillance via the wireless IP network can provide multiple benefits to the service operator, including passenger safety, staff security, and vandalism deterrence."

Williams says the capital costs invested in security infrastructure is expected to realise immediate returns in the form of:

• Reduced false insurance claims
• Reduced vandalism-associated rectification costs
• Reduced costs associated with non-availability of services, due to incident-associated disruptions
• Reduced insurance premiums, due to the risk reduction associated with an enhanced security capability.

"From a staff perspective, any enhanced personal security measures will be welcomed, both by individuals and unions, resulting in indirect benefits of improved workforce relations, increased staff loyalty and enhanced performance," Williams says.

The DLR application was selected as a finalist in the 'Applications' category by the judges at the IP in Security Innovation Awards in January 2005.

Demanding specification

The stringent and demanding specification for the on-train application required that six camera inputs were recorded in each carriage, all at real time rates, simultaneously with full resolution images, with recordings to be retained for up to 10 days before overwriting.

This equates to the capture and digitisation of 150 pictures each second across the six cameras. each unit has to withstand the climatic and mechanical type tests detailed in EN 50155, shock and vibration tests detailed in EN 61373, and electromagnetic coupling tests in EN 50121-3-2.

Wavelet Technology embarked on a modification to its established Sapphire range of Wavestore electronics and Linux-based operating system in order to meet these harsh environmental and performance criteria. The use of PC104+ industrial grade motherboards was deployed and all the electronics housed in a specially developed 3U high 19-inch rack mountable case – the size of a small briefcase.

The system, which is a large network of 600 cameras, will have one DVR fitted onboard each carriage. All six cameras will be powered from the unit, which also incorporates 2.4GHz wireless transceivers in order to maintain full network capabilities across the 27km WAN during full operation of the trains.

Remotely located security staff are able to select and view any four cameras simultaneously across the network in real time (25fps).

Wavelet Technology's proprietary encryption techniques and use of incorruptible Wavelet compression allows evidence to be admissible and presented in a court of law to aid prosecution. Williams says this comes at a time "when there are many doubts about the validity of common compression techniques such as MPEG". He believes Wavelet provides the best image quality and performance.

Remote control centre

The command and control centre utilises the IP functionality to allow an operator to seamlessly log on via a PC to any DVR and monitor or download the required images. The system transmits real time video imagery from any of the 600 cameras from any train operating in the rail network to the central monitoring station. this provides the monitoring staff with the unique ability to respond instantly to alarm activations and/or recorded incidents.

Both alarm triggered and time-lapse recordings can be searched and retrieved instantly. The recorders feature a pre-event recording feature that enables video images prior to an incident to be retained at real time rates.

Williams says Wavestore's Extended Video Interface is a simple to use, yet powerful software solution that permits CCTV installers or transport operators to design and create multiple windows for the interface and control of the system's cameras in either PAL or NTSC on any of the common PC platforms: Windows, Linux, or Apple Mac.

The program writer is given full control over the geometry and positioning of each viewing window to display any camera in any window, for both live and archived video, together with multiple synchronised audio channels. Different display options address varying security requirements, such as football matches or exhibitions.

IP feature

The IP functionality of the Diamond DVR is utilised to provide control, system status and control functionality. The transmission system design guarantees a data rate of 8Mbps using a variant of 802.11b, implemented with OFDM modulation to reduce urban multi-path fading effects.

Williams says not security system is fully effective without the ability to store and retrieve the imagery captured by its sensors.

"The ability to review an incident, using high quality and timely video evidence, is critical to successful prosecutions for illegal activities and through creating an awareness of its capabilities, significantly enhancing its credibility as a deterrent," he says.

"With over 155,000 passengers using the network each day, the system has been designed to deliver high quality video advertising as well as regular passenger information and news bulletins, delivered on high quality monitors fitted around the carriages, whilst full passenger security is maintained with simultaneous CCTV recording and remote monitoring."